Audio events, such as concerts, speeches, etc., are often held in large venues, such as stadiums, parks, arenas, etc. Delivering audio to listeners at such events is challenging because of the size of the venues and their acoustical characteristics.
In large venues, speakers broadcasting the audio may be arrayed in desirable locations to deliver audio to the audience members. Other venues may simply arrange banks of speakers on or near the stage. Despite careful placement of speakers, the quality of sound heard by the audience members may not as good as desired.
Numerous conventional devices and systems for enhancing the quality of sound heard by an audience member at an audio event have been proposed. For example, U.S. Pat. No. 7,110,552 to Saliterman describes a system designed to collect acoustic signals created at an event, wirelessly transmit them, and reproduce them to a plurality of listeners at the event who are wearing headphones, but the system makes no attempt to compensate for the propagation delay of sound.
U.S. Pat. Nos. 5,619,582 and 5,822,440 both to Oltman et al., as well as U.S. Pat. No. 7,995,770 to Simon, describe systems that do add a wirelessly-transmitted supplemental acoustic signal at a listener's ears via headphones, where the supplemental signal is also delayed to compensate for the propagation delay of the primary acoustic signal that also reaches the listener's ears directly.